The common diseases and pests of cherry
Savvas Pastopoulos, Agronomist MSc, Pastopoulos Agronomics, Neos Mylotopos, Pella, Greece
In cherry, mistakes are rarely made in the choice of product. They are made in the identification. Three entirely different agents leave holes in the leaf and call for three different decisions. Four different insects leave a maggot in the fruit and only one of them is treated at colour change. This article is a complete identification guide, diseases, pests and the one abiotic cause that imitates them all, with a tool that compares the symptoms in the orchard against the profile of each cause.
- How a symptom is read in cherry
- The identification tool
- Brown rot of blossoms and fruit
- Shot hole
- Cherry leaf spot
- Cherry leaf scorch
- Phytophthora and root rots
- Bacterial canker of stone fruit
- Crown gall
- Viruses and phytoplasmas
- The three fruit flies
- The remaining pests
- Cracking, neither disease nor pest
- Diseases and pests that get confused with one another
- The year's programme at a glance
- Sources
1. How a symptom is read in cherry
Cherry has three peculiarities that shape every diagnosis.
The window is narrow. A few weeks pass between flowering and harvest, and into them are compressed brown rot, the cherry fruit fly, cracking and spotted wing drosophila. A mistake is not corrected the following month, because the following month is after harvest.
Summer damage is paid for the next spring. Cherry leaf spot and shot hole do their greatest damage after harvest, when nobody is looking at the tree any more. Early defoliation in July and August removes from the tree exactly the time it needs to differentiate flower buds and store carbohydrates.
The same symptom has three causes. Holes in the leaf are the classic example, analysed in the table of the diseases and pests that get confused with one another. But it holds equally for the maggot in the fruit, and for the collapse of a whole tree in midsummer.
The rule that settles most cases
The leaf alone is never enough. Before deciding what it is, what else is present on the tree is checked: shot hole leaves traces on the shoots, the bacterium on cankers and dead buds, the virus in its distribution across the block.
And a second rule, for the soil-borne problems: the pattern in the field. Phytophthora appears in patches, in the low spots and wherever water stands. Capnodis strikes isolated trees under stress. Crown gall follows the planting line, because it arrived with the nursery material.
2. The identification tool
The tool compares the selected symptoms against the profiles of eighteen causes. It does not count simple matches: each symptom carries a weight according to how distinctive it is, and some count negatively. Round, regular holes in the leaf speak for shot hole and against bacterial canker, which gives irregular ones.
Select the plant part, then select whichever symptoms are observed. The results update automatically.
DisclaimerThe tool is an identification guide, not a diagnosis. It is neither a recommendation nor a treatment prescription, and it does not replace on-site assessment by a licensed agronomist. Errors or omissions in its own data cannot be excluded. Definitive identification requires laboratory examination, and for quarantine organisms it is made by the competent official authority. Any intervention is made at the user's own responsibility, on the basis of the product's approved label.
3. Brown rot of blossoms and fruit
The most important fungal disease of cherry. It attacks blossoms, fruit and twigs, where it causes brown rot. It is favoured by wet, rainy weather and overwinters in sporodochia at the base of the buds, in cankers and in mummified fruit [15].
What has changed in Greece
Monilinia fructicola is on the EPPO A2 list, it was on the A1 list from 1984 and was transferred to A2 in 2004 [1]. The EPPO list is a recommendation and not law: quarantine status in the Union is set by Regulation (EU) 2019/2072, in whose annexes the species is not included as a Union quarantine pest. It has already been detected in twelve Member States of the Union, Greece among them.
What matters is the change in population composition: the introduced M. fructicola has almost entirely displaced the native M. fructigena in the Mediterranean and now coexists with M. laxa [3]. The change was documented in Greece as well, in Imathia and Larissa, through the analysis of 145 isolates of M. fructicola from blossoms and fruit of peach, apricot, cherry and plum [2].
In practice this means that the pathogen growers are working with today is not the one of twenty years ago, and M. fructicola is known internationally for the speed with which it develops fungicide resistance.
The two windows that decide the season
Flowering. The petals, anthers and stigma are the susceptible organs of the flower. Wet weather favours primary infection, and in orchards with a history of the disease an application is recommended from white tip to the start of flowering [15]. The fungus enters through the flower, moves down the pedicel and from there into the twig, where it forms the canker. A missed spray at flowering does not cost only that season's blossom.
Ripening. The second cycle, with fruit infections. Every wound, from cracking, hail, insect or bird, is an entry point.
The cheapest and often the most neglected measure is the elimination of the initial foci: removal and destruction of all branches bearing cankers, together with mummified fruit on the trees and on the ground [15]. It costs no product and reduces the initial inoculum directly.
Rotation of modes of action, not optional
Because brown rot requires repeated sprays within the same short period, it is among the diseases with the highest risk of resistance development. Applications are made by rotating different FRAC groups, not by repeating the same active substance or the same group.
Brown rot of stone fruit, cause, symptoms, treatment: the full article
4. Shot hole
Shot hole is caused by the fungus Wilsonomyces carpophilus [5]. The name has changed several times and is still encountered as Stigmina carpophila or Clasterosporium carpophilum; phylogenetically it is clearly distinct from the genus Thyrostroma, with which it was confused [6].
The distinguishing character
The leaf lesions are circular and regular, with a clear abscission zone. The dead tissue drops out and leaves a hole with a smooth, round outline, the classic «buckshot» appearance. That regularity is the key: bacterial canker gives irregular, angular holes, because the tissue tears rather than abscising.
Shot hole is rarely confined to the leaf. It is accompanied by small lesions and cankers on the young shoots and, in wet seasons, by sunken lesions on the fruit, often with gum exudation. Where all three are present, the diagnosis is safe.
Control
Copper in winter, at leaf fall and before bud break, and contact fungicides on the new spring growth. The winter copper covers shot hole, cherry leaf spot and bacterial canker simultaneously, and is the spray with the highest return per euro in the whole year.
5. Cherry leaf spot
Cherry leaf spot is caused by Blumeriella jaapii and is the disease that costs without appearing to cost, because its damage is completed after harvest.
Symptoms
On the upper surface, very small purple to brown lesions appear at first, which multiply and coalesce. The whole leaf turns yellow and drops. The diagnostic element, however, is neither the lesion nor the yellowing: it is the whitish fruiting bodies on the lower surface, directly on the lesions, visible with a hand lens in wet weather.
Why the critical spray is the post-harvest one
Cherry leaf spot is decided in July and August, when the orchard has already been emptied and attention has moved elsewhere. In that period the tree is differentiating next season's flower buds and storing carbohydrates. A tree left bare in August enters winter with empty stores.
It is the reverse of brown rot: there the spray protects this year's crop, here it protects the next.
Cherry leaf spot (Blumeriella jaapii), field diagnosis: the full article
6. Cherry leaf scorch
Cherry leaf scorch is caused by Apiognomonia erythrostoma [7] and has one symptom it shares with no other disease of the crop: the infected leaves dry out but do not fall. They remain hanging on the tree all winter, brown and brittle.
This is not only a diagnostic character, it is also the pathogen's survival mechanism: the retained leaves carry the inoculum into the following spring. The corresponding measure is mechanical, removal and destruction of the dry retained leaves at winter pruning, together with the mummified fruit of brown rot.
Sources: 7
7. Phytophthora and root rots
The canopy symptoms are not specific: chlorosis, small leaves, reduced growth, branch dieback and, in severe cases, collapse of the whole tree. It is exactly the picture wrongly attributed to a nutrient deficiency or to the tree being «tired».
The distinguishing feature lies not in the canopy but at the crown and in the pattern. At the crown, removing the bark reveals brown to reddish rot with a clear margin against healthy tissue. In the pattern, Phytophthora appears in patches: in the low points of the block, in the rows above the drip line, wherever water is held after irrigation.
Control is mainly hydraulic rather than chemical: correcting the drainage, keeping the crown dry, moving the emitters away from the trunk, raising the planting line. Every episode of soil saturation is an episode of risk.
Phytophthora and crown rots in fruit trees: the full article.
8. Bacterial canker of stone fruit
Bacterial canker is caused by Pseudomonas syringae, with two pathovars responsible on stone fruit: pv. syringae and pv. morsprunorum, the latter with two genetically distinct races, R1 and R2 [9]. The distinction matters because they differ in aggressiveness and in host range.
Where it actually shows
On the leaf it gives lesions that are irregular, not circular, which tear and leave angular holes. But the decisive evidence lies elsewhere on the tree:
- Cankers with gum on scaffolds and twigs, exuding freely in wet periods.
- Dead buds that fail to break in spring, while their neighbours break normally.
- Brown internal discolouration beneath the bark, descending from the canker.
The measures that really count are cultural: pruning in dry weather and never before rain, disinfecting tools between trees, avoiding wounds, and choosing a rootstock and a site that do not leave the tree under stress.
Bacterial canker of stone fruit, Pseudomonas syringae: the full article
9. Crown gall
Crown gall is caused by Agrobacterium tumefaciens and gives hard, irregular galls at the crown and on the roots, more rarely higher on the trunk. The picture is almost exclusive and is hard to confuse.
The problem is not the identification but the origin: crown gall almost always arrives with the propagation material or enters through wounds at planting. That is why it frequently appears along the planting line and in young orchards.
The only effective intervention is preventive and is made before the tree goes into the ground: dipping the roots in a suspension of the antagonistic bacterium Rhizobium rhizogenes, strain K84 or the genetically stabilised K1026 [11]. The mechanism is the production of agrocin, described as early as the late 1970s [12]. For an established tree with galls there is no treatment.
10. Viruses and phytoplasmas
Viruses are the category that separates itself from all the others by a single criterion, and it is not the symptom: it is the distribution. Symptoms appear on the same trees every year, uniformly over the whole tree, most strongly on the first spring growth. No fungal or bacterial infection behaves like that.
In cherry the commonest symptoms are chlorotic rings and line patterns on the blade, distortions, and in some cases holes that imitate shot hole. The difference is that here no spray helps.
A separate case is European Stone Fruit Yellows, which is caused not by a virus but by a phytoplasma and is transmitted by an insect vector. Its picture is early reddening or yellowing of the foliage with downward curling, and progressive decline of the tree.
The virus diseases of sweet cherry in Greece: the full article
11. The three fruit flies
Three different insects leave a larva inside the cherry. Telling them apart determines both the timing and whether any intervention is needed at all.
Cherry fruit fly (Rhagoletis cerasi)
The principal pest of the crop. It has one generation a year. The female lays one egg per fruit, at colour change, and the larva feeds in the flesh around the stone. The fruit softens around the sting and darkens. One larva per fruit is the rule.
Exactly when, the figures from a phenological model
Multi-year monitoring with yellow sticky traps in cherry orchards in Türkiye, in the Bursa region, produced a forecasting model based on temperature accumulation from 1 February [13]:
- At an altitude of 150 metres, the first catches occurred from 25 May to 2 June, at an accumulation of 582.50 ± 10.50 degree-days.
- At an altitude of 1,170 metres, first adult emergence was recorded from 6 to 14 June, at 667.50 ± 14.50 degree-days.
- The optimum window for a single intervention was calculated at 577.70 to 639.40 degree-days at 150 metres and at 780.90 to 848.60 at 1,170 metres.
- Adult emergence was bimodal at low altitudes and unimodal at high ones, meaning that on the plain a single intervention misses more easily.
The model is calibrated for that particular region and requires local verification with traps before being used as a calendar.
The same study also produced a figure that puts the problem in perspective: fruit infestation was 0.1% in conventionally managed orchards and 2.2% in reduced-input orchards [13]. The cherry fruit fly is controllable, but only with correct timing.
Cultural measures that apply to both main fruit pests: harvesting all the fruit by the end of the season and incorporating any residues into the soil, and sound pruning practice for good air movement [14].
Spotted wing drosophila (Drosophila suzukii)
Unlike the other drosophilids, it attacks sound, ripening fruit, not rotten fruit. The female lays beneath the skin, and the oviposition site is recognised by two microscopic white breathing filaments protruding from it. The larvae are very small and lie close to the surface, not near the stone. The fruit «sits down», softens and leaks juice within a few hours.
In the food-trap network of the agricultural warning service it is recorded at the same time as the cherry fruit fly, and where infestations were observed a combined treatment is recommended for the late cultivars [14].
Drosophila suzukii, the spotted wing drosophila: the full article
Mediterranean fruit fly (Ceratitis capitata)
Polyphagous and late. In cherry it matters mainly in the very late cultivars and where neighbouring crops sustain it. The distinguishing character is the number: many larvae in the same fruit and a rapid, wet rot, in contrast with the single larva left by the cherry fruit fly.
The Mediterranean fruit fly: the full article.
12. The remaining pests
Black cherry aphid (Myzus cerasi)
A large, shiny, metallic black aphid. It overwinters as a shiny black egg on the twigs and fruiting spurs. The eggs hatch shortly before flowering and the population can become very large early in spring [16].
The damage is mainly a problem of young trees, where it causes curling and distortion of the leaves at the shoot tips [16]. On a bearing tree the same picture costs far less. Secondarily, the honeydew soils leaves and fruit and supports sooty mould.
The finding that changes the timing of the intervention
The population falls to very low levels on its own in summer, because the aphid migrates and survives mainly on weeds of the mustard family [16]. A summer spray against aphid in cherry chases a population that is already leaving.
The right time is dormancy or delayed dormancy. If it is missed then and the natural enemies, ladybirds, lacewings, parasitoids, are not sufficient, the intervention is made shortly after petal fall [16]. The population is assessed at flowering.
Spider mites (Tetranychus urticae, Panonychus ulmi)
Two webspinning spider mites are reported on cherry, Tetranychus urticae and Tetranychus pacificus [18], together with the European red mite Panonychus ulmi [19]. Common names are a constant source of confusion, which is why it matters that in the Greek ministry database the name «Κίτρινος Τετράνυχος» (yellow spider mite) is given explicitly alongside the scientific name Tetranychus urticae [17].
What the leaf shows. The damage begins as stippling, from the removal of the cell contents. Yellowing and leaf drop follow, and at high populations the shoot terminals are covered with webbing [18]. In Pacific Northwest data the triad is described as stippling, bronzing and possibly leaf drop [20]. The European red mite gives a finely mottled appearance and rarely causes leaf drop in cherry; it overwinters as an egg on twigs and spurs, hatches in early spring just after the trees leaf out, and completes eight to ten generations before autumn [19].
What raises the population. Dust and water stress. Preventing water stress is named explicitly as a measure, because the stressed tree carries higher mite densities and intensified damage [18]. Dry, dusty conditions, drought-stressed trees and excessive nitrogen applications all favour infestations [20]. In practice, the dirt track beside the row and the missed irrigation cost more than a wasted acaricide.
The outbreak is usually our own doing
Mite populations decline naturally, and the outbreaks that reach damaging levels usually appear after products have been used that disrupt the natural enemies [18]. In the Pacific Northwest, sufficient control is usually achieved by midsummer by the natural enemies themselves [20].
Sampling is done on at least fifteen leaves per tree. The decision does not come from the absolute number of mites but from a comparison: when the number of leaves with predators is nearly the same as the number with pest mites, no treatment is needed. Treatment is needed when the leaves with pest mites are increasing and those with predators are not [18].
Hexythiazox is classified in IRAC mode-of-action group 10A and acts by preventing hatching [21]. It is not a product that clears an established infestation of adult females. The Greek labels place it at the appearance of the infestation [17], not once the foliage has already turned bronze. Waiting for the bronzing before deciding means the window has already closed.
Approvals change, and they are valid in Greece only. The status in force is checked each time in the database of approved plant protection products [17].
Capnodis, the flat-headed root borer (Capnodis tenebrionis)
The insect that kills the tree without warning. The larva opens wide galleries in the crown and roots, and the tree collapses abruptly in midsummer, often within a few days. The adults feed on leaf petioles and the base of young shoots, and their presence on the tree is the early sign.
It targets trees under water stress, in hot dry positions and on light soils. The strongest preventive measure is not an insecticide but irrigation: a tree that is not thirsty attracts far fewer adults.
Capnodis tenebrionis, the flat-headed root borer: the full article
Wood borers, goat moth and leopard moth
They are recognised by the frass. Galleries in the trunk or scaffolds, with dirty frass and often gum at the entrance. The goat moth (Cossus cossus) works low down, at the base of the trunk and at the crown, with large-diameter galleries and a strong odour. The leopard moth (Zeuzera pyrina) works higher, in twigs and scaffolds, which then snap in the wind.
The goat moth (Cossus cossus): the borer that costs trees, not a crop, the full article
Bark and ambrosia beetles (Scolytus rugulosus, Anisandrus dispar)
The field picture is a whole fruiting spur or twig wilting with its leaves and fruit still attached, and one round hole at the base of the dead part. The hole diameter is given as about 3 mm [22].
Two different insects can lie behind the same picture.
The shothole borer (Scolytus rugulosus) works under the bark. It leaves many small round holes, which on stone fruit are often sealed with gummy ooze. It overwinters as a larva in burrows beneath the bark and adults emerge in spring, with a second generation starting in August. These figures come from Pacific Northwest data for the United States, and the number of generations in Greece has not been confirmed here [22].
Anisandrus dispar, formerly Xyleborus dispar, works inside the wood and carries with it the fungus it feeds on. The female is attracted by the ethanol emitted by stressed wood, and once established an aggregation pheromone is released that brings further beetles to the same tree. Flight begins at temperatures around 10 degrees Celsius, on a bright sunny day [23].
The species is not identified from the hole. Either the adult or the bark opened to reveal the gallery pattern is needed. The photograph documents the symptom, not the species.
The measures that hold, in the order that matters:
- Remove and destroy infested branches. This is the first measure, because the generation is completed inside them. No pile of prunings is left near the orchard [22].
- Remove the stress. Irrigation, drainage, nutrition. A tree that does not emit ethanol does not attract [23].
- Whitewash trunks of young trees against sunburn, which is an entry point [22].
- Monitor flight with an ethanol-baited trap where the problem recurs [23].
- Check neighbouring abandoned trees. Healthy trees next to neglected blocks are attacked as well [22].
Brown marmorated stink bug (Halyomorpha halys)
The feeding puncture is not visible at the moment it is made. It appears later, as a sunken lesion with hard, corky tissue beneath it and a bitter taste. In cherry the damage is mainly qualitative and appears at grading, not on the tree.
The brown marmorated stink bug, BMSB, Halyomorpha halys: the full article
13. Cracking, neither disease nor pest
Cracking enters this article for one reason: it is the commonest reason a cherry ends up rotten, and the rot that follows is charged to brown rot. The split in the skin after rain is mechanical, not pathological. Whatever enters it is secondary.
The practical consequence is that a brown rot programme in a cultivar and site with chronic cracking is chasing the symptom. Reducing cracking is a matter of cultivar, rootstock, water management, calcium and physical protection.
Reducing cracking in cherry fruit: the full article
14. Diseases and pests that get confused with one another
The pairs most often confused in the field, and the one character that separates them.
| Looks like | But is | The character that separates them |
|---|---|---|
| Shot hole | Bacterial canker | Shot hole gives circular, regular holes, with a clear abscission zone. The bacterium gives irregular, angular ones, and leaves cankers with gum and dead buds elsewhere on the tree. |
| Shot hole | A virus | A virus gives symptoms that are uniform over the whole tree and on the same trees every year, often with chlorotic rings. No spray changes the picture. |
| Cherry leaf spot | Cherry leaf scorch | In leaf scorch the dried leaves DO NOT fall, they stay hanging all winter. Cherry leaf spot drops the foliage and leaves the tree bare. |
| Cherry leaf spot | Shot hole | A hand lens on the lower surface: whitish fruiting bodies on the lesions indicate cherry leaf spot. Shot hole does not have them, but it does have cankers on the shoots. |
| Spider mite | Early cherry leaf spot | The margin. The mite leaves diffuse stippling, with no spot that has an outline. Cherry leaf spot leaves discrete purple spots and, under a hand lens on the underside, white fruiting bodies. |
| Spider mite | Nutrient deficiency or water stress | The hand lens on the underside. Motile stages, eggs and fine webbing name the mite. Without them, the greyish or bronze cast is abiotic, and then the question is water and nutrition, not an acaricide. |
| Phytophthora | Capnodis | Both give abrupt collapse in summer. Phytophthora appears in patches where water stands; Capnodis on isolated trees under drought, with galleries and frass at the crown. |
| Cherry fruit fly | Spotted wing drosophila | Spotted wing drosophila leaves two white breathing filaments at the oviposition site and its larvae are close to the surface. The cherry fruit fly leaves one larva close to the stone. |
| Cherry fruit fly | Mediterranean fruit fly | The number. The cherry fruit fly gives one larva per fruit, the Mediterranean fruit fly many, with rapid wet rot, and it prefers overripe or injured fruit. |
| Brown rot on the fruit | A crack that became infected | Look for the split beneath the rot, and relate it to rain two or three days earlier. If every rotten fruit is a cracked fruit, the problem is not fungal. |
| Crown gall | The graft union callus | The graft callus is smooth, symmetrical and at the height of the union. Crown gall gives irregular, rough galls, often below the soil surface. |
15. The year's programme at a glance
Winter, from leaf fall to before bud swell
- Copper products. They cover shot hole, cherry leaf spot and bacterial canker at the same time. The spray with the highest return per euro in the whole year.
- Pruning in dry weather, with tool disinfection between trees, and copper before and after.
- Removal of inoculum: mummified fruit from the tree and from the ground, twigs with cankers, the dry retained leaves of leaf scorch, dead shoots from the bacterium. They are burned.
- Dormancy: the right window for the black cherry aphid.
- Cleaning and painting of trunk cankers.
Spring, from bud break to fruit set
- White tip to the start of flowering: the critical window for brown rot, with rotation of FRAC groups.
- Petal fall: a second chance for the aphid, if dormancy was missed.
- New foliage: contact fungicides for shot hole and cherry leaf spot.
- Placement of monitoring traps for the cherry fruit fly, before the first expected catches.
Summer, from colour change to leaf fall
- Colour change: the window of the cherry fruit fly. Intervention where the catches and the orchard history justify it, with a follow-up at 10 to 12 days and attention to the pre-harvest interval.
- Before harvest: the second brown rot window and the spotted wing drosophila window in the late cultivars.
- After harvest: this is where cherry leaf spot is decided. Protecting the foliage in July and August determines next season's flowering.
- Harvest of all the fruit by the end of the season, with incorporation of residues into the soil.
- Irrigation control: every episode of saturation is a risk episode for Phytophthora; every episode of drought is an invitation to Capnodis.
16. Sources
The numbers in the text refer to the list below.
- [1] EPPO Datasheet: Monilinia fructicola, EPPO Global Database. Source for the quarantine status: A1 list from 1984, transfer to A2 in 2004, and presence in Member States of the Union; full text used.
- [2] Intraspecific diversity of Monilinia fructicola and M. laxa populations from blossoms and fruit of different hosts in Greece. Plant Disease. Source for the Greek data: 145 isolates of M. fructicola from Imathia and Larissa, from blossoms and fruit of peach, apricot, cherry and plum; abstract used.
- [3] Tracking of diversity and evolution in the brown rot fungi Monilinia fructicola, M. fructigena and M. laxa. Source for the displacement of the native M. fructigena by the introduced M. fructicola in the Mediterranean; full text used.
- [4] Monilinia, brown rot of stone fruit. Bugwood Wiki. Source for the relationship between the teleomorph Monilinia and the anamorph Monilia.
- [5] Wilsonomyces carpophilus (STIGCA), EPPO Global Database. Source for the current name and the synonyms of the shot hole pathogen.
- [6] First detection of Wilsonomyces carpophilus causing leaf spot and shot hole disease. Plant Health Progress. Source for the phylogenetic separation from the genus Thyrostroma; abstract used.
- [7] Apiognomonia erythrostoma (cherry leaf scorch), CABI Compendium. Source for the identity of the cherry leaf scorch pathogen and for the retention of infected leaves on the tree; full text used.
- [8] Cherry (Prunus spp.), Bacterial canker. Pacific Northwest Plant Disease Management Handbook. Source for the four reasons copper fails; full text used.
- [9] Characterization of the pathogenicity of strains of Pseudomonas syringae towards cherry and plum. Source for the separation of pv. syringae and pv. morsprunorum and for the R1 and R2 races; full text used.
- [10] Control of bacterial canker in stone fruit trees by chemical and biological products. Agronomy 13(4):1166. Source for the limits of chemical and biological intervention against bacterial canker; full text used.
- [11] Crown gall, UC IPM, University of California. Source for the use of strains K84 and K1026 as a root dip before planting; full text used.
- [12] Biological control of crown gall, Agrobacterium tumefaciens. Annals of Applied Biology. The classic paper on the agrocin mechanism; abstract used.
- [13] Kovanci, B. (2006). Reduced-risk management of Rhagoletis cerasi flies (host race Prunus) in combination with a preliminary phenological model. Journal of Insect Science 6(1):34. Source for the phenological model of the cherry fruit fly: first catches 25 May to 2 June at 150 m with 582.50 ± 10.50 degree-days from 1 February, 6 to 14 June at 1,170 m with 667.50 ± 14.50, optimum intervention window 577.70 to 639.40 and 780.90 to 848.60 degree-days respectively, bimodal emergence at low altitude, and fruit infestation of 0.1% against 2.2%; full text used.
- [14] Regional Centre for Plant Protection, Quality and Phytosanitary Control of Kavala (2024). 2nd Technical Bulletin of Agricultural Warnings for cherry, No 18/10-05-2024 (in Greek). Greek Ministry of Rural Development and Food. Source for the Greek recommendations: chemical control of the cherry fruit fly only in late cultivars and in orchards with a history, follow-up spray at 10 to 12 days, simultaneous recording of Drosophila suzukii in the same food traps and combined treatment, and the cultural measures of complete harvest with residue incorporation and pruning for air movement; full text used.
- [15] Regional Centre for Plant Protection, Quality and Phytosanitary Control of Thessaloniki (2023). Technical Bulletin of Agricultural Warnings, No 8/27-03-2023, Brown rot of cherry (in Greek). Greek Ministry of Rural Development and Food. Source for inoculum retention in mummified fruit on the tree and on the ground, for the petals, anthers and stigma as the susceptible organs, and for the recommendation to treat from white tip to the start of flowering in orchards with a history; full text used.
- [16] Grant, J.A., Caprile, J.L., Coates, W.W., Van Steenwyk, R.A., Daane, K.M. and Rijal, J.P. Black Cherry Aphid, Myzus cerasi. UC IPM Pest Management Guidelines: Cherry. UC ANR Publication 3440. Source for overwintering as a shiny black egg on the twigs, hatching shortly before flowering, damage mainly on young trees with leaf curling and distortion, the summer decline of the population through migration to mustard-family weeds, and the timing of intervention at dormancy or shortly after petal fall; full text used.
- [17] Database of approved plant protection products (in Greek), from the register of the Greek Ministry of Rural Development and Food. Source for the approval status in force in Greece by crop, active substance, rate and pre-harvest interval. Valid in Greece only.
- [18] Webspinning Spider Mites, Cherry. UC IPM Pest Management Guidelines. University of California Statewide IPM Program. Source, with California data, for the two species Tetranychus urticae and T. pacificus on cherry, for the progression of damage from stippling to yellowing and leaf drop, for the webbing on terminals at high populations, for dust and water stress as factors raising mite densities and damage, for sampling at least fifteen leaves per tree with the decision based on comparing leaves with predators against leaves with pest mites, and for the natural decline of populations and the link between outbreaks and sprays that disrupt natural enemies. Full text.
- [19] European Red Mite, Cherry. UC IPM Pest Management Guidelines. University of California Statewide IPM Program. Source for Panonychus ulmi: overwintering as an egg on twigs and spurs, hatching in early spring just after the trees leaf out, eight to ten generations before autumn, the finely mottled appearance of the leaf, and the fact that it rarely causes leaf drop in cherry. Full text.
- [20] Cherry, Spider mite. Pacific Northwest Insect Management Handbook. Source, with Pacific Northwest data from the United States, for the triad of stippling, bronzing and possible leaf drop, for dry and dusty conditions, drought-stressed trees and excessive nitrogen applications as factors favouring infestations, and for control usually achieved by midsummer by natural enemies. Full text.
- [21] Citrus Red Mite, Citrus. UC IPM Pest Management Guidelines. University of California Statewide IPM Program. Source used solely for the mode of action of the active substance hexythiazox: IRAC mode-of-action group 10A, acting by preventing hatching. The crop in the source is citrus and it is not used here for anything else. Full text.
- [22] Cherry, Shothole borer. Pacific Northwest Pest Management Handbooks. Source for the hole diameter of about 3 mm, the sealing with gummy ooze on stone fruit, overwintering as a larva beneath the bark, the two generations, the finding that injured or stressed plants are attacked and that healthy trees next to neglected blocks are at risk, and for the cultural measures. The data are from the Pacific Northwest of the United States and the number of generations does not transfer unchanged to Greece.
- [23] Pear Blight Borer, Anisandrus dispar. Oregon State University, College of Agricultural Sciences. Source for the synonymy with Xyleborus dispar, the relationship with the ambrosia fungus, attraction to ethanol from stressed wood, the aggregation pheromone, flight beginning around 10 degrees Celsius, the preference for trees under drought, waterlogging or freeze damage, and for the ethanol-baited trap. Oregon data.
The identification tool and the descriptions in this article are an aid to orientation and not a diagnosis; they are neither a recommendation nor a treatment prescription. Identification from symptoms carries inherent uncertainty: different causes give similar pictures, symptoms change with cultivar, tree age and season, and two or more problems can coexist. Errors or omissions in the tool's own data cannot be excluded. Definitive identification requires laboratory examination, and for quarantine organisms it is made by the competent official authority.
Plant protection products are used solely under the approvals of the Greek Ministry of Rural Development and Food (ΥΠΑΑΤ) and the label instructions, for the approved crop, rate and pre-harvest interval [17]. Those approvals are valid in Greece only and do not apply in other countries; readers elsewhere must follow their own national register. Active substances mentioned in foreign work are not necessarily approved in Greece. The phenological models and thresholds cited are indicative, calibrated for the regions in which they were derived, and do not constitute a recommendation for application.
Foliar sprays: any foliar application to trees carrying fruit may cause fruit marking and leaf scorch. A trial on a limited number of trees is required first, with the same product and the same rate, followed by five to seven days of observation before any general application. Spraying is done in late afternoon or early morning, never in a heatwave and never on foliage under water stress.
Any intervention is made at the user's own responsibility, following an on-site assessment by a licensed agronomist. Pastopoulos Agronomics accepts no liability for any damage arising from the use of the information in this article.
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